The invention concerns an encapsulated piezoelectric resonator device and a method for producing such a device.
Tuning fork-type quartz resonators which are encapsulated in a sealed enclosure are known, wherein the upper wall or cover of the enclosure is translucent to enable a laser beam to act on the quartz in order to adjust the frequency of the resonator.
According to the Swiss Patent Application No. 10 517/78 filed on Oct. 10, 1978, the quartz tuning fork is entirely surrounded by a frame produced from the same material. Two other frames of metal for example are fitted on respective sides of the frame of the tuning fork member and act as bracing frames to which the base plate and a cover of the resonator device will be fixed. As the two metal frames are conductors, they also serve to make the electrical connections between the inside and the outside of the enclosure, that is to say, between the electrodes on the tuning fork member and the external electrical circuit.
Although this device is relatively simple, it is made up of a relatively large number of components, which complicates assembly thereof and makes the device thick. It is known that, for a component of a watch, the thickness should be kept as small as possible. Finally, the large number of components including metal frames increases the possibility of parasitic capacitances, which has a detrimental influence on the intrinsic electrical qualities of the component.